Weightlifting barbells typically include a set of matching weight plates disposed on either end of a weightlifting bar, with a clamp disposed on the weightlifting bar outboard of the weight plates, to retain the weight plates on the bar. In addition, numerous fixturing devices use shafts to support articles at certain locations along the shafts, in which it may be desirable to use a clamp to selectively or temporarily secure the articles along the shaft at a fixed position or within a fixed range of positions.